1. Field of the Invention
The present invention relates to a coating forming device and a coatingd forming method for forming a metal coating on a surface of a substrate and, in particular, relates to a coating forming device and a coating forming method for forming a metal coating, in which a metal coating can be suitably formed by applying a voltage between an anode and a substrate.
2. Description of Related Art
In the related art, there is a case where a metal coating is formed on a surface of a substrate by depositing metal ions thereon. For example, as a technique of forming such a metal coating, a technique of forming a metal coating by plating such as electroless plating; and a technique of forming a metal coating using a PVD method such as sputtering are disclosed.
However, in a case where plating such as electroless plating is performed, a washing process is necessary after the plating, and a process of treating a waste liquid used during the washing process is also necessary. In addition, in a case where a metal coating is formed on a surface of a substrate using a PVD method such as sputtering, internal stress is generated in the formed metal coating. Therefore, the PVD method has a limit in increasing the thickness of a metal coating, and particularly in the case of sputtering, a metal coating can be formed only in a high vacuum environment.
In consideration of the above-described points, for example, a coating forming device for forming a metal coating is disclosed, the coating forming device including: an anode; a solid electrolyte membrane that is disposed between the anode and a substrate (cathode); a power supply that applies a voltage between the anode and the cathode (substrate) (for example, refer to Japanese Patent No. 5605517).
According to this coating forming device, a metal coating can be formed on a surface of a metal substrate by making the solid electrolyte membrane containing metal ions into contact with the surface of the substrate and causing the power supply to apply a voltage between the anode and the cathode (metal substrate) to deposit the metal ions on the surface of the metal substrate.
Here, when the metal coating is partially formed on the surface of the substrate using the above-described coating forming device, the following anode is used. Specifically, the surface of the anode contacting the solid electrolyte membrane includes: a coating-forming surface that has a shape corresponding to a coating-forming region of the substrate; and a non-coating-forming surface other than the coating-forming surface, and metal of the coating-forming surface has a lower oxygen overvoltage than metal of the non-coating-forming surface.
With the above-described configuration, metal of the coating-forming surface has a lower oxygen overvoltage than metal of the non-coating-forming surface. Therefore, the reactivity of deposition of metal ions on metal in a region between the coating-forming surface of the anode and the substrate can increase. As a result, metal can be deposited on the coating-forming region of the substrate opposite to the coating-forming surface. In this way, a metal coating can be formed in a pattern corresponding to the coating-forming surface without, for example, masking the surface of the substrate.